* {
    margin: 0;
    padding: 0;
}


/* 白色主题 */

:root {
    --color-menu-bg: #fff;
    --font-color-mi: #000;
    --font-color-mi-hover: #1890ff;
    --color-bg-mi-hover: #ececec;
    --border-radius-mi: 2px;
    --transition-menu-time: 0.2s;
    --color-line-bg: #d3d3d3;
}

body {
    overflow: auto;
}

.content {
    background-color: #e7e7e7;
    min-height: 100vh;
    float: left;
}

.menu-box {
    font-family: 'Trebuchet MS', 'Lucida Sans Unicode', 'Lucida Grande', 'Lucida Sans', Arial, sans-serif;
    letter-spacing: 0.5px;
    font-weight: 600;
    position: relative;
    width: fit-content;
    min-height: 100vh;
    padding: 6px 12px;
    box-sizing: border-box;
    background-color: var(--color-menu-bg);
}

.menu-box input[type='checkbox'] {
    display: none;
}

.menu-box>label {
    position: absolute;
    top: 48%;
    right: 0;
    transform: translateX(50%);
    width: 20px;
    height: 20px;
    border-radius: 20px;
    box-shadow: 0px 0px 4px 0px #000;
    background-color: var(--color-menu-bg);
    color: var(--font-color-mi);
    display: flex;
    justify-content: center;
    align-items: center;
    overflow: hidden;
}

.menu-box>label>i {
    font-weight: 900;
    text-indent: -3px;
    font-size: 20px;
    transition: transform var(--transition-menu-time);
    transform: rotate(0deg);
}

.menu-box>label:hover {
    box-shadow: 0px 0px 2px 0px #000;
    color: var(--font-color-mi-hover);
}

.menu-box>input#menu-btn:checked+label>i {
    transform: rotate(180deg);
}

.menu {
    font-size: 18px;
    width: 220px;
    min-height: 100%;
    cursor: pointer;
    overflow: hidden;
    transition: width var(--transition-menu-time);
    color: var(--font-color-mi);
}

.menu-box>input#menu-btn:checked~.menu {
    width: 0;
}

.menu-title {
    text-align: center;
    margin-bottom: 10px;
}

.menu-item>label {
    position: relative;
    width: 100%;
    height: 50px;
    border-radius: var(--border-radius-mi);
    display: flex;
    align-items: center;
}

.menu-item>label:hover {
    color: var(--font-color-mi-hover);
}

.menu-item>label>i:first-child {
    flex: none;
    margin-right: 6px;
    font-size: 24px;
}

.menu-item>label>span {
    flex: 1;
}

.menu-item>label>i:last-child {
    flex: none;
    font-size: 20px;
    font-weight: 900;
    transform: rotate(0deg);
    transition: transform var(--transition-menu-time);
}

.menu-item>input:checked+label>i:last-child {
    transform: rotate(180deg);
}

.menu-content {
    height: 0;
    overflow: hidden;
    transition: height var(--transition-menu-time);
    display: flex;
    flex-wrap: wrap;
    background-color: var(--color-menu-bg);
}


/* 选项，若 n 项，就 n * 40px */

.menu-item>input#menu-item1:checked~.menu-content {
    height: calc(3 * 40px);
}

.menu-item>input#menu-item2:checked~.menu-content {
    height: calc(2 * 40px);
}

.menu-item>input#menu-item3:checked~.menu-content {
    height: calc(3 * 40px);
}

.menu-content>span {
    width: 100%;
    text-indent: 20px;
    line-height: 40px;
    border-radius: var(--border-radius-mi);
}

.menu-content>span:hover {
    background-color: var(--color-bg-mi-hover);
    color: var(--font-color-mi-hover);
}

.set-line {
    margin: 20px 0 10px 0;
    width: 100%;
    height: 2px;
    background-color: var(--color-line-bg);
}

.frame {
    width: 100%;
    height: 974px;
    background-color: whitesmoke;
}

.frame>iframe {
    margin-left: 50px;
    width: 1600px;
    height: 973px;
}